Self-lowering jack



July Z I' 1925.

' 1,546,905 J. C. KOPF SELF LOWERING JACK Original Filed 4, 1921. s Sheets-Shec 1 Attorneu July 2; 1925. 1,546,905

J. c. KOPF SELF LOWERING JACK Original Filed Feb. 4, 1921 5 Sheets-Sheet 2 .DO I

July 21 1925. 1,546,905 J. C. KOPF SELF LOWERING JACK i inal Filed Feb. 4; 1921 5 Sheets-Sheet 3 July 21 1925. 1,546,905

J. c. KOPF SELF LOWERING JACK inal Filed Feb. 4,1921 5 Sheets-Sheet 4 llllll N July 21' 1925.

- "1,546,905 J. c. KOPF SELF LOWERING JACK Original Filed Feb. 4, 1921 5 Sheets-Sheet 5 Patented July 21, T9 25.

JOHN C. K0133, OF AKBQN, OHIO, ASSIGNOR inner innnnrnctruanve COB-L.

PANY, 0'15 PITTfiBURG-H, lENNfiYLVl-lNIA, A COXEPOR-ATIQN OF EENNS'YLVANIA,

SELF-LO'WEBING JACK.

sp ine-annealed. February 4, 192 Serial 1Y0. 442,864. Renewed, January 15, 1925.

T0 aZZ whom'z't may concern:

1 Be it known that 1, JOHN C. Kori, a

citizen of the United States, and a resident of Akron, in the county of Summit and lowering, not subject to failure in operation or to deteriorationthrough lack of attention, and susceptible of very simple and economical construction. The vertically movable load member of the jack is lifted by steep pitch screw mechanism adapted to run downiunder the load, and is lowered by a fluiddevice, which is geared to the rotary lifting screw. The instant invention contemplates more especially a fluid lowering device which holds the load at any height, and therein falls withinmy prior application Serial No. 4;19,63i, filed October 96, 1920, but differs specificallyin that the fluid does not follow the load and consequently" that a small amount of oil or other fluid is suflicient for operation; from which it follows. that the holding and lowering device can be placed either near the bottom ofthe jack to operate as long as there remains a moderate amount of lubricant in the general interior of the jac r casing, or at any suitable regions in the jack where it will work on its own reservoir or confined body of fluid. Especialsimplicity of construction and reliability of operation are secured, as will be come apparent.

In the accompanying drawings, forming a part hereof Fig. 1 is a vertical section throughthe casing of a jack embodying the invention,

interior parts being shown partly in section and partly in elevation;

. Fig. 2 is a vertical section on a larger scale on the line 22 of Fig. 1;

Fig. Sis a similar section on the line 3-3 of Fig.1; I

i Fig. 4; isa horizontal section on the line 4-4 of Fig. 1;

Fig. 5 is a vertical section on the line 5-5 Fig. 6 is a horizontal section through the lower part of the cylinder block of the fluid holding andlowering device.

The jack has a base 1, provided with a hollow standard 2 and an annex chamber 3 toward the bottom. The casing thus formed can be made tight enough to hold a supply of lubricant, which may be the same as the fluid in the holding and lowering device, or

a separate fluid may be used in the device,

which may for the jack. a p

The vertically movable load member is be thinner than the lubricant preferably in the form of a ram l slidably guided in a bearing 5 in the top of the stationary standard of the base, the top of the ram having a head 6 to act upward against the jacking point of the part to be raised. The ram is held against turning by a key 7 held in the upper part of the standard and projecting into a vertical groove 8 in the side of the ram.

The ram is hollow and its lower portion holds, or is formed as, anut 9,0r nonrotary screw member. A male screw 10 is supported rotatably on the base upon a ball bearing 11, and passes upward through the nut into the'interior of the ram.

The screw 10 is rotated to effect lifting through a horizontal main operating shaft 12 journaled in bearings 13 and 14C in the outer and inner portions of the annex, and

having on its inner end a bevel pinion 15 which meshes with a larger bevel gear 16 fixed on the lower portion of the rotary screw member. The projecting. outer end 17 of the operating shaft carries a customary ratchet lever device (not shown), whereby rotary movement of the screw in one direction, the lifting direction, is produced by oscillatory movement of a removable bar.

The threads of the screw, meaning thereby the two screw members, are to be understood as being of steep pitch, that is to say, beyond the angle of repose, so that the jack will run down by itself under the load, if not held. At such time, through the relative vertical movement of the rotary andv nourotary screw members, the screw 10 is rotated by the load in the direction reverse to that of lifting, and this inturn rotates the shaft 12 in the run-down or lowering direcmain operating shaft; and fixed on this shaft and held against longitudinal movement by the bearings is a worm 21, which meshes with a worm-wheel 22 fixed to the main shaft. The worm-wheel and worm are also of comparatively steep pitch, so that the worm will be rotated by the wormwheel.

On the shaft 18 is an eccentric .43 the eccentric st zip and pitman 24E of which is pivotally connected with the piston part of a fluid-cylinder and piston device 25 on the bottom of the chamber 3. In the preferred embodiment there are two cylinders 26 formed parallel with each other in a block,

' with two pistons 27 working in the cylinders, the piston rods 28 being connected by a two-armed rocking link 29, pivotally sup ported at the center on a bracket 30, so that the pistons are compelled to move in opposite directions.

The pistons are provided with packings 31 arranged to make a tight sliding fit with the cylinder walls 011 the downward or pressure strokes; and the cylinders, or their pressure chamber portions beneath the pistons, are filled with a fluid 32, more particularly a liquid, such as oil. The said chambers .beyond the ends of the pressure strokes of the pistons are connected by a suitably formed passage 33 (Fig. 6) also filled with the fluid, an intermediate, offset, restricted portion 34 of which passage is adapted to be firmly and tightly closed, or variably opened,

by a needle valve or its equivalent The screw stem 36 of said valve screws in and out in a bushing 37 in the block, and 'projects outward through an opening 38 in a side cover plate 39 of "the annex chamber, outside of which it presents a knob-handle 10 for ready operation by the attendant.

It will thus be seen that with the valve closed, which may be regarded as the normal condition, the effort of the load transmitted through the screw and gearing and tending to cause the jack to descend, is solidly sustained by the liquid beneath one or other of the pistons. The pressure thus transmitted is much reduced, both by the ratio of the screw members and by that of the gearing 16, 15, 22,, 21, which proceeding away from the load member constitute a speed-multiplying and therefore a powerreducing train. Consequently the fluid device can be small'and of simple and inexpensive eonstruotion, the pressure and wear upon the packings are-comparatively slight, and the load is held the more reliably against sinking, and during lowering is restrained the more safely against running away.

A one-way aeting connection or clutch interposed between the main operating shaft 12 and the fluid device 25, so thatthe lifting mechanism can be operated freely t.) raise the load. Said clutch is preferably arranged upon the auxiliary shaft 18 for a reason which will hereinafter appear. The eccentric is accordingly shown as being loose in respect to rotation upon the shaft 18 and united with a pawl carrier 11, the springpressed pawls 12 of which coact with a ratchet-wheel 4-3 fixed to the shaft. The relation of the teeth is such, it will be understood, that the shaft turns freely within the stationary eccentric in the lifting operation, but is coupled thereto in respect to pressure and rotation in the opposite direction. A spacer sleeve 44 on the shaft, between the worm 21 and the pawl-carrier and eccentric member, serves, in connection with the inward projection of the bearing 20, to keep the said member against axial displacement.

From the foregoing the operation will be readily understood. Lifting is performed by ratcheting the shaft 12 in the appropriate direction, thereby mechanically forcing the ram upward through the rotation of the screw. At each lifting stroke the lifting mechanism is automatically disconnected from the holding means by virtue of the oneway-acting clutch, which automatically at the conclusion of each stroke causes the pressure of the load, reduced as heretofore described, to be applied to the fluid 32 in one of the cylinders 31, so that the load is rigidly held. In order to lower the load, the attendant opens the valve 35, which permits fluid to pass from the cylinder chamber where it is under pressure, owing to the piston being in position to descend (or advance), into the chamber where the piston is in position to rise (or retreat). The pis tons can thus work back and forth, transferring the fluid alternately from one Cllfllllher to the other. The pistons are actuated in this manner, through the screw and gear train, the eccentric 24 and the walking-beam 29, as long as the valve remains open, or until the load reaches a support. The rate of descent is easily and exactly regulated by turning the handle d0 so as to increase or decrease the extent of opening in the fluid passageway; stopping at any point is e feoted by closing the valve, the closing being gradual, though prompt, so that shock is avoided.

The illustrated construction with two cylinders and pistons is a simple and advantageous form of fluid device geared to the load-chamber, which is double-acting or continuously acting in lowering and always ready at other times to act as a holding device; but other forms may be employed. In the preferred embodiment the fluid acted upon by the pistons is a confined and e11- closed body, and cannot escape, but is mere ly transferred past the holding valve back and forth from one chamber to another, automatically opening and closing Valves being rendered unnecessary. Any slight loss occurring over aperiod of time maybe automatically replenished by fluid entering past the packings 31on the alternate up ward or idle strokes of the pistons. In this connection, it may be noted that the pistonrod-guiding caps in the upper ends of the cylinders are provided with holes 46, throughwhich oil or other fluid may enter and which also permit the free egress of air on the upstrokes.

One end 47 of the shaft 18 extends outside of the casingand is made polygonal in order that it may receive a crank-handle 4:8, seen in Fig. 2. The shaft'18 being positively geared'to the main operating shaft 12,,in respect to rotation in both directions,

(the one-way-acting clutch being between shaft 18 and the holding and lowering means), it is thus possible quickly to run the jack up to the load, preparatory to lifting, and also to run it down when unloaded, in which event the weight of the ram is likely to be insuliicient to cause it to go down by itself. Forthe purpose of this feature the holding and retarding means may be of other specific characters.

While the invention contemplates specifically an incompressible fluid, in the holding device, it is not necessarily'limited in all cases to the use of a liquid, since air or other ga's confined under a sufficient degree of compression would be the substantial equivalent. In such case, the force of the load, greatly diminished by means of the gearing, would i not produce an appreciable reduction in the volume of the already compressed gas, and

the sinlcback at the ends of the lifting strokes would be correspondingly slight, or negligible. I

What Iclaim as new is:

1. In a self-lowering jack, having a base and a vertically movable load member, vertical screw means for lifting comprising a screw which is rotated in one direction to effect lifting and inthe opposite direction by the action of the load in lowering, and fluid-holding means operatively connected with saidscrew to hold it indefinitely against rotation and thereby hold the load at any height to which the latter may be lifted by the screw.

2. In a self-lowering jack, the combination of a steep-pitch lifting screw, a fluidholding device geared to the lifting screw so as to hold the same against rotation under the action of the load, and an operators device cooperating with said fluid-holding device to bring about lowering and stopping of the load. 7

8. In a jack, a base, a load member, and

interposed lifting mechanism, in combinati on with a fluid-holding device, and gearing including a one-way-acting clutch between said fluid-holding device and the load mem her and lifting mechanism.

In a jack, a base, a load member, and

interposed lifting mechanism, in combinat10n with a fluid-holdmg device, gearing including a one-way-actmg clutch between said fluid-holding device and the load member and lifting mechanism, and means for controlling said fluid-holding device for lowering and stopping the load.

5. In a self-lowering jack, having a base and a vertically movable load member, vertical screw means for lifting comprising a screw which is rotated in one direction to tical screw means for lifting comprising a screw whlch 1S rotated 111 one direction to effect lifting and in the opposite direction by the action of the load in lowering, a fluid-holding device, multiplying connections and a one-way-acting clutch between the rotary screw and said device.

7. In a self-lowering jack, having a base and a vertically movable load member, vertical screw means for lifting comprising a screw which is rotated in one direction to effect lifting and in the opposite direction by the action of the load in lowering, a fluidholding device operatively connected with the rotary screw and having a passageway and means for opening and closing said passageway to effect lowering and stopping of the load.

8. In a selfslowering jack, having a base and a vertically movable load member, vertical screw means for lifting comprising a screw which is rotated in one direction to effect lifting and in the opposite direction by the action of the load in lowering, mechanism comprising multiplying connections and a one-way-acting clutch arranged to be driven by the screw, a fluid-holding device connected to be driven by the screw through said mechanism and adapted to act continuously to force fluid during lowering, a passageway through which the fluid thus forced must pass, and means for opening and closing said passageway to effect lowering and stopping of the load.

9. In a self-lowering jack, having a base and a vertically movable load member, vertical screw means for lifting comprising a screw which is rotated in one direction to efiect lifting and in the opposite direction by the action of the load in lowering, a fluid-holding device comprising a plurality of cylinders and a connecting passage through which fluid is transferred back and forth between the'cylinders, a plurality of pistons in different positions, gearing and a one-way-acting clutch between said pistons and the rotary screw, and a valve closing said passage and adapted to be opened to effect lowering,

10 In a jack, the combination of a rotary steep pitch lifting screw, a main operating shaft connected therewith, an auxiliary shaft geared to the main operating shaft so as to be driven by the main shaft and also capable of driving the main shaft in both directions, a rotary member, holding means cooperating with said member, a one-wayacting clutchbetween said member and the auxiliary shaft, and means for manually rotating said auxiliary shaft.

11. in a self-lowering jack, the combination with a rotary steep-pitch lifting screw and means for rotating said screw to lift the load, of an auxiliary shaft geared to the screw in such manner as to be driven therefrom and also to be capable of driving the screw in both directions, an auxiliary handle applied to said shaft for turning it in either direction, holding and retarding means, and a one-way acting connection between said shaft and the holding and retarding means.

12. In a self-lowering jack, having a base and a vertically movable load member, vertical screw means for lifting comprising a screw which is rotated in one direction to effect lifting and in the opposite direction by the action of the load in lowering, a fluid-holding device containing a confined body of fluid in a plurality of chambers, multiplying gearing and a one-way-acting clutch between the screw member and said 7 JOHN G. KOPF, 

